The present invention relates to an electronic apparatus and a control method therefor, and more preferably, to an electronic apparatus, such as a portable electronic timepiece apparatus, having a built-in storage device and a drive motor, and to a control method for such an electronic apparatus.
Recently, small electronic timepieces, such as wristwatches, which have a built-in generator device, such as a solar cell, and which can be operated without the need for replacing batteries have been realized.
These electronic timepieces are provided with a function of temporarily charging power generated in the generator device into, for example, a large-capacitance capacitor, and when power is not being generated, time is indicated by the power discharged from the capacitor.
Accordingly, such electronic timepieces can be stably operated for a long time without batteries, and by considering the effort required to replace batteries and the problem of disposing of them, it can be expected that many electronic timepieces will have a built-in generator device.
As such an electronic timepiece having a built-in generator device, there is an analog electronic timepiece disclosed in Japanese Examined Patent Publication No. 3-58073.
In this analog electronic timepiece, a rotation detecting circuit for detecting the rotation of a motor used for driving hands is constructed in such a manner that a detection resistor device is selected from a plurality of detection resistor devices in accordance with the performance of the motor.
In the above-described related art, in selecting the detection resistor device in accordance with the performance of the motor, the following problem may occur. If a detection resistor device which increases the detection sensitivity is selected, AC magnetic noise which is caused by the operation of a generator device which would not normally be detected in detecting AC magnetic fields is disadvantageously detected. As a result, it may be erroneously detected that the motor is rotated, though it is not actually rotated.
Because of such erroneous detection, the driving of the motor cannot be reliably controlled.
Accordingly, it is an object of the present invention to provide an electronic apparatus and a control method therefor in which the driving of a motor can be reliably controlled by reducing the influence of noise caused by, for example, a leakage flux of a generator device.
A first aspect of the present invention is characterized by including: a power generator portion for performing power generation; a storage portion for storing electric energy obtained by the power generation; a single or a plurality of motors driven by the electric energy stored in the storage portion; a pulse driving controller for controlling the driving of the motor by outputting a driving pulse signal; a rotation detecting portion for detecting whether the motor is rotating by comparing a rotation detecting voltage corresponding to an induction voltage generated in the motor caused by the rotation of the motor with a rotation reference voltage; a state detecting portion for detecting a generation state of the power generator portion or a charging state of the storage portion caused by the power generation; and a voltage setting portion for setting the rotation detecting voltage or the rotation reference voltage based on the generation state of the power generator portion or the charging state of the storage portion detected by the state detecting portion so that a difference between the rotation detecting voltage in a no-rotation period and the rotation reference voltage is increased.
A second aspect of the present invention is characterized in that, in the first aspect of the present invention, the voltage setting portion may include a voltage shifting portion for relatively shifting the voltage level of the rotation detecting voltage to a no-rotation side by a predetermined amount.
A third aspect of the present invention is characterized in that, in the first aspect of the present invention, the state detecting portion may include a charging detecting portion for detecting whether the charging is performed in the storage portion.
A fourth aspect of the present invention is characterized in that, in the first aspect of the present invention, the state detecting portion may include a power-generation magnetic-field detecting portion for detecting whether a magnetic field is generated by the power generation of the power generator portion.
A fifth aspect of the present invention is characterized in that, in the second aspect of the present invention, the rotation detecting portion may include a rotation-detecting impedance device, and the voltage shifting portion may include an impedance reducing portion for effectively reducing the impedance of the rotation-detecting impedance device.
A sixth aspect of the present invention is characterized in that, in the fifth aspect of the present invention, the rotation-detecting impedance device may include a plurality of auxiliary rotation-detecting impedance devices, and the impedance-reducing portion may effectively reduce the impedance of the rotation-detecting impedance device by short-circuiting at least one of the plurality of auxiliary rotation-detecting impedance devices.
A seventh aspect of the present invention is characterized in that, in the fifth aspect of the present invention, the rotation-detecting impedance device may include a plurality of auxiliary rotation-detecting impedance devices, and the impedance-reducing portion may effectively reduce the impedance of the rotation-detecting impedance device by switching the plurality of auxiliary rotation-detecting impedance devices.
An eighth aspect of the present invention is characterized in that, in the fifth aspect of the present invention, the rotation-detecting impedance device may include a resistor device.
A ninth aspect of the present invention is characterized in that, in the first aspect of the present invention, there may be provided a chopper amplifier portion for performing chopper amplification on the induction voltage and for outputting the amplified induction voltage as the rotation detecting voltage, and the voltage setting portion may include an amplification-factor reducing portion for reducing an amplification factor of the chopper amplifier portion based on the generation state of the power generator portion or the charging state of the storage portion detected by the state detecting portion.
A tenth aspect of the present invention is characterized in that, in the ninth aspect of the present invention, the amplification-factor reducing portion may include a voltage-drop-device inserting portion for inserting a voltage drop device in a path of a chopper current generated by the chopper amplification.
An eleventh aspect of the present invention is characterized in that, in the ninth aspect of the present invention, the chopper amplifier portion may perform the chopper amplification at a frequency corresponding to a chopper-amplification control signal, and the amplification-factor reducing portion may set the frequency of the chopper-amplification control signal in a detection period of a predetermined generation state or a predetermined charging state caused by the power generation to be higher by a predetermined amount than the chopper-amplification control signal in a no-detection period of the predetermined generation state or the predetermined charging state.
A twelfth aspect of the present invention is characterized in that, in the ninth aspect of the present invention, the chopper amplifier portion may set a chopper duty in a detection period of the charging to be greater or smaller than the chopper duty in a no-detection period of the charging, which is a reference chopper duty.
A thirteenth aspect of the present invention is characterized in that, in the first aspect of the present invention, the voltage setting portion may include a voltage shifting portion for shifting the voltage level of the rotation reference voltage to a rotation side by a predetermined amount relative to the rotation detecting voltage based on the generation state of the power generator portion or the charging state of the storage portion detected by the state detecting portion.
A fourteenth aspect of the present invention is characterized in that, in the thirteenth aspect of the present invention, the voltage shifting portion may include a reference-voltage selecting portion for selecting one of a plurality of basic rotation reference voltages as the rotation reference voltage based on the generation state of the power generator portion or the charging state of the storage portion detected by the state detecting portion.
A fifteenth aspect of the present invention is characterized in that, in the fourteenth aspect of the present invention, the state detecting portion may detect the charging state based on a charging current flowing in the storage portion.
A sixteenth aspect of the present invention is characterized in that, in the fourteenth aspect of the present invention, the state detecting portion may detect the charging state based on a charging voltage of the storage portion.
A seventeenth aspect of the present invention is characterized in that, in the second aspect or the thirteenth aspect of the present invention, the pulse driving controller may output a rotation-detecting pulse signal used for detecting the rotation by the rotation detecting portion after the lapse of a predetermined period from an output of the driving pulse signal, and the voltage shifting portion may set terminals of a coil forming the motor in a closed loop during the predetermined period based on the generation state of the power generator portion or the charging state of the storage portion detected by the state detecting portion.
An eighteenth aspect of the present invention is characterized in that, in the seventeenth aspect of the present invention, the voltage shifting portion may set a frequency of the driving pulse signal in a detection period of a predetermined generation state or a predetermined charging state to be lower than a frequency in a no-detection period of the predetermined generation state or the predetermined charging state based on the generation state of the power generator portion or the charging state of the storage portion detected by the state detecting portion.
A nineteenth aspect of the present invention is characterized in that, in the second aspect or the thirteenth aspect of the present invention, the driving pulse signal may include a plurality of auxiliary driving pulse signals, and the voltage shifting portion may set an effective power of the last auxiliary driving pulse signal in an output period of the driving pulse signal to be greater than an effective power of the other auxiliary driving pulse signal in the output period of the driving pulse signal.
A twentieth aspect of the present invention is characterized in that, in the first aspect of the present invention, the electronic apparatus may be portable.
A twenty-first aspect of the present invention is characterized in that, in the first aspect of the present invention, the electronic apparatus may include a timepiece portion for performing a timing operation.
According to a twenty-second aspect of the present invention, in a control method for an electronic apparatus which includes a power generator portion for performing power generation, a storage portion for storing electric energy obtained by the power generation, a single or a plurality of motors driven by the electric energy stored in the storage portion, and a pulse driving controller for controlling the driving of the motor by outputting a driving pulse signal, the control method is characterized by including: a rotation detecting step of detecting whether the motor is rotating by comparing a rotation detecting voltage corresponding to an induction voltage generated in the motor caused by the rotation of the motor with a rotation reference voltage; a state detecting step of detecting a generation state of the power generator portion or a charging state of the storage portion caused by the power generation; and a voltage shifting step of shifting the voltage level of the rotation detecting voltage to a no-rotation side by a predetermined amount relative to the rotation reference voltage based on the generation state of the power generator portion or the charging state of the storage portion detected in the state detecting step.
According to a twenty-third aspect of the present invention, in a control method for an electronic apparatus which includes a power generator portion for performing power generation, a storage portion for storing electric energy obtained by the power generation, a single or a plurality of motors driven by the electric energy stored in the storage portion, and a pulse driving controller for controlling the driving of the motor by outputting a driving pulse signal, the control method is characterized by including: a rotation detecting step of detecting whether the motor is rotating by comparing a rotation detecting voltage corresponding to an induction voltage generated in the motor caused by the rotation of the motor with a rotation reference voltage; a state detecting step of detecting a generation state of the power generator portion or a charging state of the storage portion caused by the power generation; and a voltage shifting step of shifting the voltage level of the rotation reference voltage to a rotation side by a predetermined amount relative to the rotation detecting voltage based on the generation state of the power generator portion or the charging state of the storage portion detected in the state detecting step.